1997 pete 379 battery draw

Does anyone have a good wiring diagram for a 1997 Peterbilt 379. The one I been looking at are not that great.

 

Maybe I'm doing something wrong. 1. No fuses in fuse box.(c.b.'s still connected). 2. doors closed. 3. Radio disconnected and removed. 4. Alternator disconnected. I have the positive cables connected to starter, and batteries. Negative cables are connected to starter. When I connect the first cable to the negative post, I'm good, But when I connect the second cable, I get sparks and when I use the amp clamp, it reads 26 DCA.

 

Thanks to everyone for their input on my situation. I have never had a NEW, BAD battery before. Go Figure .... Now I hope that I resolved the first dead battery issue during this adventure. I think I covered everything else that could have gone wrong. Oh Well, On the road again !!